Cardiac pump implantation device and method

ABSTRACT

A system and method for implanting a ventricular assist device (“VAD”) within the heart includes one or more tools, each having a body with a passage. Each tool body can be engaged with an anchor ring assembly secured to the heart. A coring tool can be advanced through the passage in a tool body and used to from a hole in the heart wall, and then valve actuating elements carried on the tool can be used to close a valve incorporated in the anchor ring assembly. A VAD can be passed into the heart through a passage in a tool body after opening the valve. The procedure can be performed while the heart continues to beat, without gross blood loss.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S.Provisional Patent Application No. 62/089,910, filed Dec. 10, 2014, thedisclosure of which is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to devices and methods for installingpumps or other devices within the heart of a patient.

Ventricular assist devices (“VAD”) are used to assist the heart of apatient suffering from heart failure. A VAD includes a pump having aninlet and an outlet. The pump is installed within the body of thepatient, with the inlet of the pump communicating with a vein of thepatient and with the outlet of the pump communicating with an artery.For example, where a VAD is used to assist the left ventricle of theheart, the inlet of the pump is in communication with the leftventricle, whereas the outlet is in communication with the aorta.

As described, for example, in U.S. Patent Application Publication No.2009/0203957, the disclosure of which is hereby incorporated byreference herein, it has been proposed to mount a VAD with the housingof the pump disposed inside the heart. The pump may have an inlet at aproximal end of the housing and an outlet at a distal end of thehousing. An outlet tube is connected to the distal end of the housingand projects through a valve of the heart into the appropriate artery.For example, where the VAD is used to assist the left ventricle, theoutlet tube projects through the aortic valve into the aorta, so thatthe outlet of the pump is in communication with the aorta.

As described in the aforementioned patent publication, the housing ofthe pump may be connected by an elongated member to a proximal housingremote from the pump. Electrical connections extend through theelongated member from the proximal housing for connection to acontroller and power source. In use, a device known as a sewing ring isfastened in place on the exterior of the heart. The sewing ring has abore extending through it. The surgeon fastens the sewing ring in placeon the exterior of the heart, typically at the apex of the heart. Thesurgeon makes a hole in the wall of the heart inside the bore of thesewing ring. The device is advanced through the bore and the hole in adistal direction, with the outlet tube and pump housing leading and withthe proximal housing trailing.

The pump is advanced in this way until the pump is positioned with theoutlet cannula projecting through the valve, and with the proximalhousing disposed inside the sewing ring and projecting out of theexterior of the heart. A clamp associated with the sewing ring is thentightened so as to secure the proximal housing of the pump to the sewingring, and thus fasten the pump in place in the heart. It is desirable toinstall such a pump without arresting the heart beat and without the useof a cardiopulmonary bypass machine. In such a procedure, commonlyreferred to as an “off-pump” procedure, the surgeon must form the holeand install the pump in the heart while the heart continues beating. Asthe heart beats, it tends to forcefully expel blood through the hole.Moreover, the pump should be introduced into the heart without alsointroducing a bolus of air into the interior of the heart. While askillful surgeon can successfully perform an off-pump installation ofsuch a pump without fatal blood loss or air embolism, furtherimprovements would be desirable.

BRIEF SUMMARY OF THE INVENTION

One aspect of the invention provides systems for installation of aventricular assist device. A system according to this aspect of theinvention desirably includes an anchor ring assembly. The anchor ringassembly may include an anchor ring adapted for fastening to the wall ofthe heart. The anchor ring assembly desirably defines a bore havingproximal and distal ends, the distal end of the bore facing toward thewall of the heart when the anchor ring is fastened to the wall of theheart. The anchor ring assembly may further include one or more valveelements movable between a closed position in which the one or morevalve elements substantially occlude the bore and an open position inwhich the one or more valve elements do not substantially occlude thebore.

The system preferably includes at least one tool. Each tool desirablyincludes a tool body having proximal and distal ends, aproximal-to-distal axis extending therebetween, and a passage extendingbetween the ends of the body along the proximal to distal axis.Preferably, the distal end of the body is adapted to releasably engagethe anchor ring assembly so that the passage communicates with the borein the anchor ring assembly. Each tool desirably includes one or morevalve actuating elements movably mounted to the body, the valveactuating elements being mechanically linked to the valve elements whenthe body is engaged with the anchor ring assembly. The tool desirablyalso includes a control element operatively connected to the valveactuating elements so that the valve elements can be moved between theopen and closed positions by actuating the control element, at least apart of the control element being disposed remote from the distal end ofthe body.

A further aspect of the invention provides methods of installing atleast part of a ventricular assist device. A method according to thisaspect of the invention desirably includes the steps of providing ananchor ring assembly on the wall of the heart, and forming a holethrough the wall of the heart so that a bore in the anchor ring assemblycommunicates with the hole. The method preferably further includes thesteps of occluding the bore and connecting an installation tool to theanchor ring assembly so that a passage in the installation toolcommunicates with the bore in the anchor ring assembly adjacent a distalend of the installation tool. The method preferably also includes thestep of inserting a component of a ventricular assist device into thepassage of the installation tool and filling the passage with a liquidso that the liquid displaces air from around the component. The methodpreferably also includes the step of removing the occlusion from thebore and, while maintaining liquid around the component, advancing thecomponent through the bore and passage at least partially into the heartso that the component occludes the bore. The method may further includethe steps of securing the component in place and removing theinstallation tool.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially exploded perspective view depicting certaincomponents used in a system according to one embodiment of theinvention.

Each of FIGS. 2 and 3 is a partially exploded perspective view depictingthe components of FIG. 1 in conjunction with additional components ofthe system.

FIG. 4 is a cut-away perspective view depicting the components shown inFIGS. 2 and 3 in an assembled condition during one phase of operation.

FIG. 5 is a sectional view taken along line 5-5 in FIG. 4.

FIG. 6 is a perspective, partially exploded view depicting additionalcomponents used in the system of FIGS. 1-5.

FIG. 7 is a fragmentary, diagrammatic perspective view depicting certainelements of a system according to a further embodiment of the invention.

FIG. 8 is a diagrammatic plan view depicting certain elements of asystem according to another embodiment of the invention.

FIG. 9 is a diagrammatic elevational view depicting certain componentsof a system according to yet another embodiment of the invention.

DETAILED DESCRIPTION

A system according to one embodiment of the invention includes an anchorring assembly 10 depicted in FIG. 1. The anchor ring assembly includesan anchor ring 12. Anchor ring 12 includes a generally hoop-likemetallic body 14. Body 14 has a flange 16 at a distal end, a generallycylindrical exterior surface 18 projecting in the proximal direction Pfrom flange 16, and a further small flange 20 projecting outwardly fromthe exterior surface at the proximal end of the anchor ring. The anchorring is hollow and has a generally spherical interior surface (notshown). The anchor ring has a slot 22 extending through it at onelocation on its circumference. The slot allows the anchor ring to becompressed slightly so as to reduce its diameter and thus reduce theinterior diameter of the spherical interior surface. Anchor ring 12 isintended to be fastened to the exterior of the heart during use. Forthis purpose, the anchor ring is provided with a fabric ring 24 attachedto flange 16. The anchor ring can be secured to the exterior surface ofthe heart by stitching the fabric ring to the heart in a conventionalmanner.

Other structures that are capable of anchoring the anchor ring to thewall of the heart may be used instead. For example, as disclosed in U.S.Provisional Patent Application No. 61/894,117, the disclosure of whichis incorporated by reference herein, the anchor ring may be providedwith metallic anchoring elements that penetrate into the heart muscle soas to secure the anchor ring in place on the exterior surface of theheart.

Anchor ring 12 further includes a gimbal element 26 mounted insideanchor ring 14. The gimbal element 26 has a spherical exterior surface28 engaged with the spherical interior surface of the anchor ring.Gimbal element 26 is also hollow and defines an interior bore 30extending in the proximal direction P and distal direction D. Thespherical exterior surface of the gimbal element allows the gimbalelement to tilt slightly relative to the anchor ring. Gimbal element 26also has a slot 32 extending through it at one point on itscircumference. Thus, when anchor ring 12 is compressed as discussedabove, gimbal element 26 will also be compressed so as to reduce thediameter of bore 30.

The anchor ring 12 further includes a clamp ring 34 extending around theexterior of the cylindrical surface 18 of the anchor ring. The claimring 34 is engaged between the distal flange 16 and the proximal flange20. Clamp ring 34 has a pair of diametrically opposed cut-outs 39, onlyone of which is visible in FIG. 1. Clamp ring 34 also has a slot (notshown) extending through it at one point on its circumference. A pair ofclamp arms 36 project outwardly from the clamp ring on opposite sides ofthe slot. A link 38 is pivotally mounted to one of the arms 36 andprojects across the slot to the opposite arm 36. A screw 40 isthreadedly engaged with one of the arms. The axis of the screw extendsgenerally in the proximal and distal directions, with the head of thescrew facing in the proximal direction. The screw has a generallyconical cam surface 42 facing in the distal direction. By engaging atool in the head of screw 40 and rotating the screw, the cam surface 42can be forced in the distal direction so that it engages link 38 andpulls the arms 36 closer to one another. This action tightens the clampring 34 and thus constricts the anchor ring 14 and the gimbal element26, thereby reducing the diameter of bore 30.

The anchor ring assembly further includes a valve 40. Valve 40 includesa valve housing formed by a pair of valve housing elements 42 a and 42b. Each housing element includes a proximal section 44 and a distalsection 46. The proximal and distal sections of each housing element 42are permanently fastened to one another. The proximal section 44 of eachhousing element has a generally semicircular wall 48 projecting in theproximal direction. Each wall 48 has lips 61 projecting outwardly fromthe wall and extending in the proximal-to-distal direction.

The distal section 46 of each housing element has a recess 52. Eachhousing element also has a catch 50 that projects slightly from thesurface of the recess.

Housing element 42 a has a pair of pins 54, of which one is visible inFIG. 1, whereas the opposite housing element 42 b has a pair of holes56. The housing elements can be releasably secured to one another byengaging pins 54 in holes 56. Housing element 42 a has a hole 58extending through its semicircular wall 48. As shown in FIG. 2, housingelements 42 a and 42 b, when engaged with one another, cooperativelydefine a bore 60. The housing elements can be secured to anchor ring 12in the assembled condition shown in FIG. 2 by assembling the housingelements to one another and engaging the catch element 50 in one of thecut-outs 39 in the clamp ring. (FIG. 1.) In this condition, the catchelements 50 are engaged under the proximal flange 20 of the anchor ringbody so that the assembled housing elements are locked to the anchorring. In this condition, the bore 60 defined by the assembled valvehousing elements constitutes a continuation of the bore 30 extendingthrough anchor ring 12.

Valve elements 62 a and 62 b are slidably mounted to valve housingelements 42 a and 42 b respectively. The valve elements are slidablebetween the closed position depicted in solid lines in FIG. 1 and anopen position partially depicted in broken lines at 62 a′ and 62 b′. Inmoving from the closed position to the open position, the valve elementstravel in directions transverse to the proximal-to-distal directions andtransverse to the axis 63 (FIGS. 1, 2) of the combined bore defined bythe valve housing elements and anchor ring. When the valve elements arein the closed position, they substantially abut one another andsubstantially occlude the bore. Valve element 62 a has a hole 64 in theend of the valve element facing away from the axis of the bore. Valveelement 62 b has a similar hole (not shown).

The system further includes a preparation tool and coring device shownin FIGS. 2, 3, and 4. The preparation tool includes a preparation toolbody 66 having a proximal end 68, a distal end 70, and a cylindricalpassage 72 extending between the proximal and distal ends and defining aproximal-to-distal axis 74. Passage 72 has an enlarged section 76 (FIG.4) at its distal end. As best seen in FIG. 5, body 66 has a pair ofkeyways 78 extending proximally-to-distally within the enlarged section76 of passage 72.

A groove 80 extends proximally-to-distally on the exterior surface ofbody 66. Body 66 also has a pair of grooves 82 extending transverse tothe axis 74 on one surface of the housing. These grooves are spacedapart from one another in the proximal-to-distal direction. Body 66 alsohas a pair of pockets 84 formed on opposite surfaces of the body at thedistal end 70. The body further has a proximal stop hole 86 a and adistal stop hole 86 b extending into the body from one surface.

The preparation tool further includes a catch lever 90 having aprojection 92 at one end and a handle 94 at the opposite end. The catchlever 90 is pivotably mounted to body 66 by a pivot pin 98, so that thehandle 94 is disposed adjacent the proximal end 68 of body 66. The catchlever is movable between an engaged position and a disengaged position.The engaged position is depicted schematically in FIG. 5. In thisengaged position, projection 92 extends into the enlarged portion 76 ofthe passageway through a hole (not shown) in body 66. In the disengagedposition, projection 92 is retracted out of the enlarged portion 76 ofthe passageway. A biasing element biases the catch arm toward theengaged position. The biasing element may be a spring schematicallyrepresented at 98 in FIG. 2.

The preparation tool further includes a pair of valve actuating elements100. The valve actuating elements have pins 102 projecting from theirdistal ends. The valve actuating elements 100 also have guide pin holes104 remote from their distal ends. A set of guide pins 106 are receivedin the guide pin holes 104 of the valve actuating elements. The guidepins are also received in the slots 82, best seen in FIG. 3). As bestseen in FIG. 4, the proximal portions of valve actuating elements 100overlie the surface of body 66 bearing slots 82.

A slide plate 110 has central slots 112 extending through it. Thecentral slots extend in the proximal-to-distal direction. The slideplate also has pairs of oblique slots 114 extending through it. Theoblique slots are oblique to the proximal-to-distal direction of theslide plate and converge with one another in the distal direction. Slideplate 110 also has an operating hole 116 at its proximal end. Slideplate 110 overlies the proximal portions of valve actuating elements100, so that the proximal portions of the valve actuating elements aresandwiched between the slide plate and body 66. The guide pins 106associated with the valve actuating elements are engaged in the obliqueslots 114 of the slide plate.

A cover plate 120 overlies the slide plate 110. The cover plate is fixedto body 66 by bolts (not shown). Cover plate 122 has a pair of bosses122 projecting from it. These bosses are engaged in the central slots112 of slide plate 110. Thus, slide plate 110 is constrained to moverelative to housing 66 only in the proximal-to-distal direction. Valveactuating elements 100 are constrained by pins 106 and slots 82 to moveonly in directions T transverse to the proximal-to-distal direction.

As depicted in FIGS. 4 and 5, the slide plate 110 is in a fullyretracted position, at the proximal limit of its travel. In thiscondition, valve actuating elements 100 and hence pins 102 projectingfrom the distal ends of the valve actuating elements are close to oneanother and relatively close to the central axis 74 of the passageway inbody 66. An operator can grasp slide plate 110 by its proximal end as,for example, by grasping the slide plate at operating hole 116 and movethe slide plate in the distal direction. Upon such movement, theengagement between the guide pins 106 (FIGS. 2 and 3) and the obliqueslots 114 forces the guide pins and hence valve actuating elements 100to move away from one another in the transverse direction T. Theengagement between the guide pins 106 and slots 82 in the body 66prevents the valve actuating elements and guide pins from movingdistally with the slide plate. Thus, distal motion of the slide platecauses the valve actuating elements 100 to move away from one another,to the open position indicated in broken lines at 100′ in FIG. 5. Movingthe slide plate proximally relative to the housing causes the valveactuating elements 100 to move towards one another, back to the closedposition indicated solid lines in FIG. 5.

The system according to this embodiment of the invention furtherincludes a coring tool. The coring tool includes a tubular housing 130.A handle 132 is fixed to the housing 130 at the proximal end thereof. Agenerally cylindrical anvil 134 is fixed to housing 130 at the distalend of the housing. Anvil 134 defines a cutting surface 136 facing inthe distal direction and forming the distal end of the housing 130.Handle 132 and anvil 134 have holes 138 and 140 extending through themin the proximal-to-distal direction. These holes are coaxial with thecylindrical exterior surface of housing 130

A shaft 144 is slidably received in holes 138 and 140. A coring element146 is fixed to the distal end of shaft 144. Coring element 146 isgenerally in the form of a hollow cylindrical shell with a conicalexterior surface 147 at its distal end. The coring element has a sharp,circular edge at its proximal end. An operating knob 150 is fixed toshaft 144 at its proximal end. A ring 152 is secured to shaft 144. Acompression spring 154 surrounds shaft 144, and is engaged between ring152 and anvil 134. Spring 154 normally keeps shaft 144 and coringelement 146 in the retracted position shown. In this retracted position,coring element 146 is engaged with surface 136 at the distal end ofhousing 130. However, an operator can move the shaft and coring elementin the distal direction relative to the housing by displacing actuatingknob 150 distally.

A stop lever 160 is pivotally mounted to the handle 132 of the coringdevice. Stop lever 160 has an enlarged head 162 at its distal end and astop pin 164 projecting from the head. As best appreciated withreference to FIG. 4, an operator can swing head 162 away from thehousing 130 of the coring tool by forcing the proximal end of lever 160towards shaft 144. A spring 166 schematically indicated in FIGS. 2 and 4biases the distal portion of the lever and head 162 toward the housing130.

As shown in FIG. 4, the housing 130 of the coring tool is slidablyreceived within the passage 72 of the body 66 of the preparation tool.Desirably, the exterior diameter of housing 130 forms a close butslidable fit with the inside diameter of passage 72. As depicted in FIG.4, the coring tool is in a storage position. In this position, the stoppin 164 of the stop actuation lever 160 is engaged in proximal stop hole86 a and the coring tool does not extend distally beyond the body 66.

The preparation tool can be engaged with the anchor ring assembly 10.The slide plate 116 is to bring the valve actuating elements 100 to theclosed position depicted in FIG. 5. Catch lever 90 is moved to thedisengaged position to retract projection 92 out of the enlarged portion76 of the passage. With the preparation tool in this condition, and withthe valve elements 62 a and 62 b in the closed position shown in solidlines in FIG. 1, the distal end of the coring tool can be placed overthe tubular structure formed by walls 48 forming the proximal end of thevalve housing. The preparation tool can be rotated about its axis 74 soas to bring keyways 78 (FIG. 5) into alignment with the lips 61 of thevalve. As the preparation tool body 66 is advanced distally toward theanchor ring assembly 10, the pins 102 on the valve actuating elementsenter into the holes 64 (FIG. 1) on the valve elements. At the sametime, the tubular structure formed by the proximal projecting walls 48of the valve body is telescopically received within the enlarged section76 of the passage in preparation tool body 66. The lips 61 act as keysand enter into the keyways 78 in the enlarged portion of the passageway(FIG. 5). This keying action assures that the valve body of the anchorring assembly is in a predetermined alignment with the features of theanchor ring assembly. Thus, the pins 102 of the valve actuating elementswill be aligned with the holes 64 of the valve element. Also, hole 58 onthe valve body (FIG. 1) is aligned with the projection 92 of latch 90.Once the valve body has been fully seated into the enlarged section 72of the passage, the operator releases the latch lever 90 and thus theprojection 92 enters into hole 58. This locks the entire anchor ringassembly in a predetermined position relative to the body 66 in theproximal and distal directions.

With the preparation tool body 66 locked to the anchor ring assembly inthis manner, the bore defined by the anchor ring assembly, including thebore 60 of the valve assembly and the bore 30 of the anchor ring, iscontinuous with the passage 72 in the preparation tool body 66. Thevalve elements 62 can be moved to their open position by an operatorgrasping slide plate 110 as by engagement feature 116 and moving theslide plate in the distal direction. This moves the valve operatingelements 100 outwardly. The pins 102 on the valve elements move thevalve elements outwardly to the open position. When the valve elementsare in their open position, the bore of the anchor ring assembly issubstantially unoccluded. The operator can bring the valve elements backto their closed position by moving the slide in the proximal direction.In the closed position, the valve elements 62 substantially occlude thebore in the anchor ring assembly.

Typically, the coring tool is engaged in the preparation tool bodybefore the preparation tool body is engaged with the anchor ringassembly. Ordinarily, when the coring tool body is first engaged withthe anchor ring assembly, the coring tool is in the storage positiondepicted in FIG. 4, with the stop pin 162 engaged in the proximal stophole 86 a. As further discussed below, the coring tool is brought to anadvanced position to core the muscle of the heart. To move the coringtool to the advanced position, the operator moves the valve elements tothe open position as discussed above and actuates the stop lever 160 todisengage the stop pin from the proximal stop hole 86 a. The operatorcan then slide the coring tool housing 130 distally within the passage72 of the coring tool body until the stop pin 162 engages the distalstop hole 86 b under the influence of spring 166. This stops the coringtool at the advanced position. In this advanced position, the cuttingsurface 136 forming the distal end of the coring tool body is alignedwith the distal side of anchor ring 14, and the coring element 146projects distally beyond the anchor ring. The coring tool can be movedback to the storage position by reversing these steps.

The system according to this embodiment of the invention desirablyfurther includes an installation tool 200 depicted in FIG. 6.Installation tool 200 has a body 266 with a proximal end 268, a distalend 270, and a passage 272 extending between the proximal and distalends of the body. Body 266 also has a slot 202 extending entirelythrough one wall and extending from the proximal end of the body to thedistal end. Slot 202 communicates with passage 272. The walls of slot202 define a pair of grooves 204, of which one is visible in FIG. 6.

Passage 272 has an enlarged section (not shown) at its distal end,identical to the enlarged section 76 of the preparation tool body (FIG.5). The enlarged section is provided with key slots similar to slots 78discussed above with reference to FIG. 5 and also has a latch openingsimilar to the corresponding feature of the preparation tool bodydiscussed above. In this embodiment, the installation tool body 266 islonger in the proximal-to-distal direction than the preparation toolbody 66 discussed above. The other features of the installation toolbody 266 may be identical to the corresponding features of thepreparation tool body.

The installation tool further includes a closure element 206 formed froma resilient, liquid-impervious material such as a rubber or arubber-like polymer. The closure element is in the form of an elongatedstrip having an inner surface 208 and ridges 210 projecting from sidesurfaces remote from the inner surface. Inner surface 208 is in the formof fragment of a cylindrical surface having radius equal to the radiusof the cylindrical passageway 272 in the installation tool body. Theclosure element or strip 206 is normally positioned in slot 202 withridges 210 received in the grooves 204 of the slot. In this position,the inner surface 208 is substantially continuous with the inner surfaceof passage 272 and the strip substantially closes slot 202.

While the closure element 206 is in place within slot 202, it seals theslot so that the walls of body 266 bounding passageway 272 between itsproximal and distal ends are substantially fluid-tight. However, closureelement 206 can be dislodged progressively along the length orproximal-to-distal extent of body 266 so as to progressively open slot202 along the length of the body. Thus, closure element 206 serves as ameans for progressively forming an opening in installation tool body 266along its length.

The installation tool 200 further includes valve actuating elements 220,a slide plate 230, and a cover 240. These elements are identical to thecorresponding valve actuating elements 100, slide plate 110, and cover120 of the preparation tool discussed above. The valve actuatingelements 220, slide plate 230, and cover 240 are mounted to theinstallation tool body 266 in exactly the same manner as thecorresponding components of the preparation tool and function in thesame way. Likewise, a latch lever 290 is mounted to insertion tool body266 in the same manner as the latch lever 90 discussed above withreference to the preparation tool.

The insertion tool can interact with and engage the anchor ringassembly, including the valve body and the valve elements in exactly thesame manner as the preparation tool discussed above. For example, whenthe distal end 270 of the insertion tool valve body is engaged with theanchor ring assembly 10, the anchor ring assembly, and specifically thegenerally cylindrical wall 48 defined by the valve body (FIGS. 1 and 2),is telescopically received within the enlarged section of the passageway272 in the insertion tool body 266. The latch on lever 290 is engaged inthe hole 58 in the cylindrical wall of the valve body, so that theanchor ring assembly is locked in place relative to the installationtool body. Here again, the bore in the anchor ring assembly communicateswith the passage 272 in the installation tool body. Also, the valveactuating elements 220 are engaged with the valve elements 62 of theanchor ring assembly by means of the pins 222, one of which is visiblein FIG. 6, carried by the valve actuating elements. In exactly the samemanner as discussed above with reference to the preparation tool, theoperator can actuate the slide element 230, as by engaging theengagement hole 216 at the proximal end of the slide to move the valveelements 220 from their closed position to the open position.

A VAD 300 (FIG. 6) used with the tools discussed above may be generallyas disclosed in the aforementioned U.S. Patent Application PublicationNo. 2009/0203957. The VAD includes a pump body 302 and internalcomponents such as an impeller (not shown) and electrical coils formoving the impeller within the pump body 302. The pump body 302 definesan inlet 304 at its proximal end. An outlet tube 306 communicates withthe pump body and projects distally from the pump body. The outlet tubehas outlet apertures 308 at its distal end. The VAD further includes acylindrical base body 310. Base body 310 may have a passageway 312schematically indicated in FIG. 6 extending through the base body fromits proximal end 314 to its distal end 316. Passageway 312 is closed bya removable closure 318 at the proximal end of the base body. Aprojection 320 extends from the base body in a direction transverse tothe axis of the base body and thus transverse to the proximal and distaldirections. An electrical cable 322 is connected to the base body bymeans of projection 320. A strut 324 mechanically connects the base body310 and pump body 302. Electrical conductors from cable 322 extendthrough the base body and through strut 324 to the pump body.

Cable 322 may be connected to a controller (not shown) mountable withinthe body. Alternatively, cable 322 may extend to a skin-penetratingelectrical connection, which in turn is connected to an externalcontroller. In yet another alternative, cable 322 may be arranged toextend through the skin of the patient when the VAD is mounted in thepatient's body.

In a pump implantation method according to one embodiment of theinvention, the surgeon makes an incision in the patient's chest so as toexpose the apex of the heart. The incision may be relatively small as,for example, about 5 cm in diameter. The surgeon then attaches theanchor ring 12 (FIG. 1) to the wall of the heart adjacent the apex ofthe heart. At this time, the clamp of the anchor ring is open, so thatthe clamp ring 34 is relaxed and the anchor ring 12 and gimbal 30 arenot compressed. The anchor ring is attached with the distal surface (thesurface facing downwardly in FIG. 1) abutting the wall of the heart andwith the proximal flange 20 of the anchor ring facing away from theheart. The surgeon may make a small starting incision through the wallof the heart inside the bore 30 of the anchor ring. The incision may be,for example, in the form of two cuts crossing one another to form anx-shape. With the small incision, some blood will leak from the heart asthe heart continues to beat. However, such blood loss will not be sosubstantial as to be immediately life-threatening.

The surgeon then assembles the valve to the anchor ring by assemblingthe valve housing elements 42 a and 42 b with one another and engagingthe projections 50 (FIG. 1) under the proximal flange 20 of the anchorring. Desirably, the valve elements 62 a and 62 b are in their closedpositions when the valve elements are assembled with one another. Oncethe valve elements have been assembled with one another, the valveelements substantially occlude the bore 30 in the anchor ring. In avariant of this procedure, the surgeon may assemble the valve housingelements 42 a and 42 b with one another and engage the same with theproximal flange of the anchor ring before making the incision, and maymanually bring the valve elements 62 a and 62 b to their open position.In this condition, the surgeon can make the incision through the bore 60(FIG. 2) in the valve body and through the bore 30 of the anchor ring.After making the incision, the surgeon may manually move the valveelements back to their closed positions so as to substantially occludethe bore in the anchor ring assembly.

The valve elements in their closed position need not form a perfectseal. Some seepage of blood may occur even when the valve elements areclosed. However, the valve elements in their closed position occlude thebore sufficiently to avoid any gross loss of blood that would beimmediately threatening to the patient.

With the valve in place on the anchor ring and the valve elements in theclosed position, the surgeon engages the preparation tool (FIGS. 2, 3,and 4) with the anchor ring assembly in the manner described above. Atthis time, the coring tool is desirably in place within the passage 72of the preparation tool. The surgeon then manipulates the slide plate110, as by grasping engagement hole 116 and forcing the slide platedistally, so as to bring the valve elements to their open position. Thesurgeon can do this readily, because the engagement hole 116 in theslide plate is remote from the distal end of the preparation tool bodyand remote from the heart. For example, the engagement hole 116 mayprotrude out of the patient's body or may be within the incision closeto the surface of the patient's body. With the valve elements in theopen position, some blood will flow into the distal end of thepassageway in the preparation tool body. However, the housing 130 of thecoring tool substantially occludes the passageway and prevents grossloss of blood.

With the valve elements in the open position, the housing of the coringtool is advanced distally by manipulating handle 132. The pointed end ofcoring element 146 enters the heart and forces tissue aside. The distaltravel of the coring tool housing and coring element is arrested whenthe distal end 162 of the stop lever 160 becomes aligned with the distalstop hole 86 b in the coring tool body (FIGS. 2 and 4), so that the stoppin 164 on the stop lever engages the distal stop hole 86 b. In thiscondition, the cutting surface 136 on the distal end of the coring toolhousing is aligned with the distal surface of the anchor ring 12 andthus aligned with the exterior surface of the heart wall.

The surgeon then actuates the coring tool by forcing operating knob 150,and hence shaft 144 and coring element 146, distally relative to thecoring tool housing and hence relative to the anchor ring andpreparation tool body. The displaced tissue becomes engaged between thecutting edge 148 (FIG. 2) of the coring element 146 and the cuttingsurface 136 at the distal end of the coring tool housing. The surgeonthen retracts actuating knob 150 and hence the coring elementproximally, so that the engaged tissue is cut by the cutting edge andcaptured inside the hollow coring element 146. This forms a hole in thewall of the heart having a diameter just slightly less than or equal tothe diameter of the bore in the anchor ring assembly. Typically, thisdiameter is about 18 millimeters. However, because the housing 130 ofthe coring tool continues to substantially occlude the passage 72 in thepreparation tool body, there is only minimal blood seepage from theheart. The coring tool is then retracted to the retracted positiondepicted in FIG. 4 by pulling handle 132 proximally.

The surgeon then actuates the slide plate to move the valve actuatingelements 100 and the valve elements 62 to their closed position. Withthe valve elements in the closed position, the surgeon then actuates thelatch lever 90 of the preparation tool to release the preparation toolfrom the anchor ring assembly and withdraws the preparation tool andcoring tool from the patient's body. At this time, the bore in theanchor ring assembly is again substantially occluded by the valveelements 62 so that there is no massive blood loss but, at most, someblood seepage.

The surgeon positions the VAD within the passage 272 of the insertiontool 200 (FIG. 6). At this stage, the closure element 206 is disposed inslot 202. The VAD is positioned in the passageway of the installationtool so that the proximal end 314 of the base body 310 projects out ofthe proximal end 268 of the installation tool body. The remainder of thebase body, including the distal end 316, is disposed within passage 272and substantially occludes the passage. The projection 320 on the basebody is aligned with slot 204. The distal end of the outlet cannula 306is disposed adjacent the distal end of the installation tool body 266.The surgeon then engages the distal end 270 of the installation toolwith the anchor ring assembly, so that the latch on the latch lever 290(FIG. 6) is engaged with the hole 58 in the valve housing of the anchorring assembly. The valve elements 62 of the anchor ring assembly remainclosed. In this condition, the valve elements 62 substantially occludepassageway 272 and separate the passageway from the bore 30 in theanchor ring. Stated another way, the passageway 272 is substantiallyoccluded at both ends by the base body 310 of the VAD and by the valveelements.

At this stage, the space within the passageway surrounding the VAD as,for example, the space between the base body 310 and pump body 302 andthe space surrounding the outflow cannula 306 may be full of air.Likewise, the space inside pump body 302 and outflow cannula 306 alsomay be filled with air. The surgeon may remove closure 318 of the basebody (FIG. 6) and insert a cannula (not shown) through the passage 312in the base body. The surgeon may insert a liquid such as salinesolution through the passageway so as to flush the space within thepassageway 272 of the installation tool body and the space within thepump and outflow cannula. Alternatively, the surgeon may remove closure318 and briefly open the valve elements 62 by actuating the slide 220 ofthe installation tool so that blood advances into the space withinpassageway 272 and the space inside the pump. As the blood advances, airis forced out through the passage 312 in the base body. When the basehas been purged in this manner, a small amount of blood will begin toleak from the assembly through the passageway 312 in the base body. Thesurgeon may then reinstall the closure 318.

With the valve elements in the open position, the surgeon advances theVAD distally within passageway 272. As the surgeon advances the VAD, theVAD passes through the anchor ring and into the heart. As the VAD movesdistally, projection 320 passes into slot 202. The surgeon progressivelypeels closure element 206 out of the slot so as to allow the projection320 to pass distally within the slot as the VAD advances. During thisstage, however, the slot remains substantially sealed by the closureelement at all locations distal to the distal end 316 of the base body310. Thus, the space within the passageway 272 distal to the base body,as well as the space within the VAD itself, remains substantially fullof liquid. As the VAD advances, the outflow tube 306 of the VAD isadvanced through the ventricle of the patient's heart and into an arteryas, for example, into the aorta. At the same time, the pump body 302 isadvanced through the bore in the anchor ring assembly and into theventricle. This action continues until the base body 310 is engaged inthe bore 30 of the anchor ring.

At this time, the clamp of the anchor ring is actuated, as by turningscrew 40 using a screw driver (not shown) passed along the outside ofthe installation tool. The clamp is actuated to compress the anchor ring12 and the gimbal 30, thereby locking the base body 312 into the anchorring and plugging the anchor ring. The surgeon then actuates latch lever290 to release the installation tool and slides the installation toolproximally away from the anchor assembly, leaving the VAD in place. Asthe surgeon moves the installation tool in this manner, the projection320 exits through the distal end of slot 204.

The surgeon may then remove the valve body from the anchor ring bymanually pulling the valve housing elements 42 a and 42 b away from oneanother, thereby releasing the valve housing elements from the anchorring. At this juncture, installation of the VAD within the heart iscomplete. The VAD may be started and operated in the normal manner toassist the patient's circulation.

Numerous variations and combinations of the features discussed above canbe utilized without departing from the present invention. For example,the installation tool described above with reference to FIG. 6 can alsobe used as the preparation tool. That is, the coring device can beintroduced through the passage 272 of the installation tool and thenremoved after formation of the hole in the heart wall and closure of thevalve elements. After removal of the coring device, the VAD can beintroduced into the passage of the installation tool. The installationtool may be provided with stops such as the stop holes 86 a, 86 b (FIGS.2 and 4) used to control the motion of the coring device housing asdiscussed above. The stops used to control motion of the coring devicecan be varied. For example, a stop may be provided at the proximal endof the preparation tool housing to engage the handle 132 of the coringdevice and thus arrest motion of the coring device housing at theretracted position shown in FIG. 4. The stop may be removable to permitadvancement of the coring device. The handle may be arranged to engagethe proximal end of the preparation tool body when the coring devicehousing is in the advanced position, with the distal end of the coringdevice coplanar with the distal surface of the anchor ring.

In the embodiments discussed above, the valve elements are slidablymounted to the valve body for sliding motion between their open andclosed positions. However, in other variants, the valve elements may bearranged to swing about pivots on the valve housing so as to open andclose. In the embodiments discussed above, two valve elements areemployed. However, more than two valve elements, or only one valveelement, can be used, provided that the valve element or valve elementssubstantially occlude the bore when the same are in their closedposition. The valve elements should be substantially clear of the borewhen they are in their open position, so that the valve elements do notsubstantially obstruct the bore in the open position.

In the arrangements discussed above, the proximal end of the slide plate110 and the engagement hole 116 at the proximal end of the slide plateserve as a control element, which the surgeon or other operator maygrasp and manually operate to move the valve elements. This controlelement is mechanically linked to the valve actuating elements by theslide plate itself and the guide pins, so that the valve actuatingelements can be moved between their open and closed positions by movingthe control element. However, other forms of mechanical linkage betweenthe control element and the valve actuating elements can be employed.For example, any arrangement of cams, levers, gears, belts, pulleys, orother mechanical elements that are operative to move the valve actuatingelements responsive to operation of the control element can be employed.The linkage between the control element and the valve actuating elementsneed not be mechanical. Pneumatic, hydraulic, or electromechanicalelements such as motors and solenoids can be used to drive the valveactuating elements responsive to actuation of the control element.

Further, in the embodiments discussed above, the valve actuatingelements are directly linked to the valve elements by the pins on thevalve actuating elements when the tool is coupled to the anchor ringassembly. However, the valve actuating elements may be indirectly linkedto the valve elements by components incorporated in the anchor ringassembly as, for example, by operating handles or linkages included inthe valve itself.

In the embodiments discussed above, the valve is detachable from theanchor ring so that the valve can be removed from the patient afterinstallation of the VAD. In other embodiments, however, the valve may bepermanently attached to the anchor ring. In still other embodiments, thevalve may be formed with a unitary housing that is attachable to theanchor ring and detachable from the anchor ring by structures such asthreads or a bayonet lock.

In the embodiments discussed above, the removable closure element 206(FIG. 6) serves to form an opening in the wall of the installation toolhousing, which opening progresses in the proximal-to-distal direction.However, other structures that can accomplish this function may be used.For example, as schematically depicted in FIG. 7, the installation toolbody 466 may be provided with a pair of resilient lips 402 thatcooperatively close a slot 404 in the body communicating with thepassage 472 of the body. The resilient lips are arranged so that as theprojection 420 on the base body 410 of the VAD moves distally, theprojection displaces the resilient lips in the immediate vicinity of theprojection to form an opening 401. The opening 401 travels progressivelyin the distal direction D as the VAD continues to move in the distaldirection.

In a further arrangement schematically depicted in FIG. 8, theinstallation tool body 566 has a similar slot 504. The slot 504 iscovered by a plate 501 having an edge 503 oblique to the proximal anddistal directions. Plate 501 is slidably or pivotally mounted to body566 for movement of the plate in a direction generally transverse to theproximal and distal directions. The plate is also arranged to bearagainst the surface of the housing and seal slot 504 in regions coveredby the plate. As the projection 520 on the VAD 510 moves distally, theplate is displaced in the transverse direction T, thus uncovering slot504 progressively in the distal direction and forming the progressivelyadvancing opening.

In still other embodiments, where the VAD does not incorporate aprojection extending in directions transverse to its axis, thearrangement for performing the advancing opening in the wall of theinstallation tool may be omitted.

As discussed above with reference to FIGS. 1 and 5, the anchor ringassembly includes a locking mechanism actuating by turning a screw 40.When the preparation tool or installation tool is engaged with theanchor ring assembly, the anchor ring assembly lies in a predeterminedrotational position around the axis of the passage in the tool as, forexample, in a predetermined orientation around axis 674 (FIG. 9)maintained by engagement between the lips 61 of the valve housing andthe slots 678 in the distal end of the tool. As schematically depictedin FIG. 9, the preparation or installation tool body 666 may be providedwith features such as an auxiliary passage 602 formed in the body or ina structure 604 attached to the body extending proximally and distally.This passage 602 lies at a predetermined position relative to thefeatures 678 of the body 666 that align the anchor ring assembly withthe tool body. The position of auxiliary passage 602 is selected so thatwhen the anchor ring assembly is engaged with the anchor ring assembly,passage 602 will be aligned with the head of the screw 40 (FIG. 1) thatactuates the clamp. A tool 606, such as a screw driver, may be advancedthrough the auxiliary passageway to the screw 40 on the clamp. The toolbody thus serves to guide the driver and facilitate engagement of thedriver with the actuating feature of the clamp. Similar arrangements canbe used where the clamp incorporates features other than a screw.

As these and other variations and combinations of the features describedabove can be employed, the foregoing description of certain embodimentsshould be taken as illustrating rather than as limiting the presentinvention. Certain aspects of the present invention are furtherdescribed by the numbered paragraphs set forth below.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. A system for installation of a ventricular assist device comprising:(a) an anchor ring assembly including an anchor ring adapted forfastening to the wall of the heart, the anchor ring assembly defining abore having proximal and distal ends, the distal end of the bore facingtoward the wall of the heart when the anchor ring is fastened to thewall of the heart, the anchor ring assembly further including at one ormore valve elements movable between a closed position in which the oneor more valve elements substantially occlude the bore and an openposition in which the one or more valve elements do not substantiallyocclude the bore; (b) at least one tool, each said tool including: (i) atool body having proximal and distal ends, a proximal-to-distal axisextending therebetween, and a passage extending between the ends of thebody along the proximal to distal axis, the distal end of the body beingadapted to releasably engage the anchor ring assembly so that thepassage communicates with the bore; (ii) one or more valve actuatingelements movably mounted to the body, the valve actuating elements beingmechanically linked to the valve elements when the body is engaged withthe anchor ring assembly; and (iii) a control element operativelyconnected to the valve actuating elements so that the valve elements canbe moved between the open and closed positions by actuating the controlelement, at least a part of the control element being disposed remotefrom the distal end of the body.
 2. A system as claimed in claim 1wherein, in each said tool, the valve actuating elements include distalportions disposed adjacent the distal end of the body and the distalportions are movable in directions transverse to the proximal-to-distalaxis.
 3. A system as claimed in claim 2 wherein, in each said tool, thedistal portions of the valve actuating elements include pins projectingin the distal direction of the tool body, and wherein the valve elementsof the anchor ring assembly include holes, the pins being engaged in theholes when the tool is engaged with the anchor ring assembly.
 4. Asystem as claimed in claim 2 wherein, in each said tool, the distalportions of the valve actuating elements are movable in directionstowards and away from the proximal-to-distal axis.
 5. A system asclaimed in claim 1 wherein the control element of each said tool ismovably mounted to the body.
 6. A system as claimed in claim 5 whereineach said tool includes a mechanical linkage operatively connecting thecontrol element and the valve actuating elements.
 7. A system as claimedin claim 5 wherein the control element of each said tool is movablerelative to the body in the proximal and distal directions.
 8. A systemas claimed in claim 1 wherein the anchor ring assembly includes a valvehousing releasably connectable to the anchor ring, the valve elementsbeing movably mounted to the valve housing.
 9. A system as claimed inclaim 8 wherein the valve housing defines the proximal end of the boreand the anchor ring defines the distal end of the bore when the valvehousing is connected to the anchor ring.
 10. A system as claimed inclaim 9 wherein the valve housing is adapted to telescopically engagethe body of each said engagement tool.
 11. A system as claimed in claim9 wherein the valve housing includes a plurality of valve housingelements which are releasably engagable with one another, the valvehousing elements cooperatively defining the proximal end of the borewhen engaged with one another and connected to the anchor ring.
 12. Asystem as claimed in claim 1 wherein the at least one tool includes aninstallation tool and wherein the tool body of the installation toolincludes a major portion having a slot extending between the proximaland distal ends of the body and a closure element releasably received inthe slot.
 13. A system as claimed in claim 12 further comprising aventricular assist device adapted for insertion into the heart of apatient through the passage of the installation tool and the bore of theanchor ring assembly, the ventricular assist device including a cableadapted to pass through the slot of the installation tool body when theclosure element is not received in the slot.
 14. A system as claimed inclaim 1 wherein the at least one tool includes a preparation tool, thesystem further comprising a cutting device adapted to be received in thepassage of the preparation tool body and to engage the wall of the heartthrough the bore of the valve assembly.
 15. A system as claimed in claim14 wherein the cutting device is a coring device having a housing withproximal and distal ends, a coring element movably mounted to thehousing and wherein the housing of the coring device is adapted to beslidably received in the passage of the preparation tool body.
 16. Asystem as claimed in claim 15 wherein the preparation tool includes afirst stop adapted to releasably hold the housing of the coring devicein a first position so that the coring element will be proximal to thevalve elements when the coring element is in the retracted position. 17.A system as claimed in claim 16 wherein anchor ring has a distal surfaceadapted to bear on the wall of the heart and the preparation toolincludes a second stop adapted to releasably hold the housing of thecoring device in an advanced position wherein the distal end of thehousing of the coring device is aligned with the distal surface of theanchor ring, and wherein the coring element is mounted to the housingfor movement relative to the housing in a distal direction from aretracted position in which the coring element is engaged with thehousing and an extended position in which the coring element is remotefrom the housing.
 18. A method of installing at least part of aventricular assist device component comprising the steps of: (a)providing an anchor ring assembly on the wall of the heart; (b) forminga hole through the wall of the heart so that a bore in the anchor ringassembly communicates with the hole; (c) occluding the bore; (d)connecting an installation tool to the anchor ring assembly so that apassage in the installation tool communicates with the bore in theanchor ring assembly adjacent a distal end of the installation tool; (e)inserting a component of a ventricular assist device into the passage ofthe installation tool and filling the passage with a liquid so that theliquid displaces air from around the ventricular assist device; (f)while maintaining liquid around the component, removing the occlusionfrom the bore and advancing the component through the bore and passageat least partially into the heart so that the component occludes thebore; (g) securing the component in place and (h) removing theinstallation tool.
 19. A method as claimed in claim 18 wherein anelongated connector extends from the component and remains outside ofthe heart after step (f), the method further comprising the step offorming an elongated opening in a wall of the installation tool so thatthe opening extends along the length of the passage, the step ofremoving the installation tool including passing the elongated connectorthrough the opening.
 20. A method as claimed in claim 18 wherein thestep of inserting a component includes inserting a distal portion of thecomponent into the passage of the installation tool so that a projectionon a proximal portion of the installation tool projects from thecomponent in a lateral direction transverse to the passage and beyond alateral extent of the passage, the method further comprising the step ofprogressively forming an elongated opening in the wall of the passage sothat the opening progresses in the proximal to distal direction, thestep of forming the opening being performed at least in part during thestep of advancing the component includes advancing the projection intothe elongated opening.
 21. A method as claimed in claim 20 wherein,during the advancing step, the liquid is maintained in a portion of thepassage distal to the opening.
 22. A method as claimed in claim 18further comprising the step of connecting a preparation tool to theanchor ring assembly before forming the hole, the step of forming thehole including the step of cutting the heart wall with a cutting toolwhile a housing of the cutting tool is disposed in a passageway of thepreparation tool communicating with the bore, and then retracting thecutting tool into the passageway of the preparation tool before the stepof occluding the bore, the cutting tool housing and preparation toolsubstantially blocking blood flow out of the bore prior to the step ofoccluding the bore.
 23. A method as claimed in claim 22 furthercomprising removing the preparation tool after the step of occluding thebore and before connecting the installation tool.
 24. A method asclaimed in claim 23 wherein the step of occluding the bore includesactuating a valve carried on the anchor ring assembly by operating acontrol connected to the preparation tool and disposed remote from theanchor ring assembly, and wherein the step of removing the occlusionfrom the bore includes actuating the valve by operating a controlconnected to the installation tool and disposed remote from the anchorring assembly.
 25. A method as claimed in claim 18 wherein the stepwherein the anchor ring assembly includes an anchor ring and a valve,the steps of occluding the and removing the occlusion from the boreincluding actuating the valve.
 26. A method as claimed in claim 25further comprising the step of removing the valve from the anchor ringafter the step of advancing the component.
 27. An installation tool fora ventricular assist device comprising a tool body having proximal anddistal ends, a proximal-to-distal axis extending therebetween, and apassage extending between the ends of the body along the proximal todistal axis, the distal end of the body being adapted to releasablyengage an anchor ring assembly, the tool body including a major portionhaving a slot extending between the proximal and distal ends of the bodyand a closure element releasably received in the slot.
 28. A tool asclaimed in claim 27 wherein the closure element is flexible andresiliently engaged with the tool body so that the closure element canbe dislodged from the tool body progressively along the length of thetool body.
 29. An installation tool for a ventricular assist devicecomprising a tool body having proximal and distal ends, aproximal-to-distal axis extending therebetween, and a passage extendingbetween the ends of the body along the proximal to distal axis, thedistal end of the body being adapted to releasably engage an anchor ringassembly, the tool body including means for selectively forming anopening in the tool body extending between the proximal and distal endsof the body.
 30. A tool as claimed in claim 29 wherein the means forselectively forming the opening is operative to form the openingprogressively along the length of the slot starting from the proximalend of the tool body.
 31. A system for installation of a ventricularassist device comprising: (a) an installation tool as claimed in claim27; and (b) an anchor ring assembly including an anchor ring adapted forfastening to the wall of the heart, the anchor ring assembly defining abore having proximal and distal ends, the distal end of the bore facingtoward the wall of the heart when the anchor ring is fastened to thewall of the heart, the anchor ring assembly further including a valveoperative to limit outflow of blood from the heart through the bore, thedistal end of the tool body being adapted to engage the anchor ringassembly so that the passage communicates with the bore.
 32. A system asclaimed in claim 31 wherein the valve includes one or more valveelements movable between a closed position in which the one or morevalve elements substantially occlude the bore and an open position inwhich the one or more valve elements do not substantially occlude thebore and wherein the installation tool includes (i) one or more valveactuating elements movably mounted to the body, the valve actuatingelements being mechanically linked to the valve elements when the bodyis engaged with the anchor ring assembly; and (ii) a control elementdisposed remote from the distal end of the body and operativelyconnected to the valve actuating elements so that the valve elements canbe moved between the open and closed positions by moving the controlelement.
 33. A system as claimed in claim 32 further comprising apreparation tool, the preparation tool including: (i) a tool body havingproximal and distal ends, a proximal-to-distal axis extendingtherebetween, and a passage extending between the ends of the body alongthe proximal to distal axis, the distal end of the body being adapted toreleasably engage the anchor ring assembly so that the passagecommunicates with the bore; (ii) one or more valve actuating elementsmovably mounted to the body, the valve actuating elements beingmechanically linked to the valve elements when the body is engaged withthe anchor ring assembly; and (iii) a control element disposed remotefrom the distal end of the body and operatively connected to the valveactuating elements so that the valve elements can be moved between theopen and closed positions by moving the control element.
 34. A valveassembly comprising: (a) a plurality of valve housing elements, thevalve housing elements being releasably engagable with one another toform a valve housing having a bore, the valve elements having engagementfeatures adapted to secure the valve housing to an anchor ring when thevalve housing elements are engaged with one another and to allow removalof the valve housing elements from the anchor ring when the valvehousing elements are disengaged from one another; and (b) a plurality ofvalve elements, each valve element being movably mounted to one of thevalve housing elements, the valve elements being selectively movablebetween a closed position in which the valve elements substantiallyocclude the bore and an open position in which the valve elements do notsubstantially occlude the bore.